Dyes and photographic emulsion and elements containing said dyes

ABSTRACT

Novel polymethine cyanine dyes are derived from certain enamines containing a cyclohexene ring having a reactive methylene or methyl substituent thereon. These dyes are spectral sensitizers for photographic silver halide emulsions and sensitize such emulsions up to wavelengths ranging about from 550 mu to 770 mu. Many of the dyes are useful sensitizers for the red to near infrared regions of the spectrum.

United States Patent [191 Fumia, Jr. et al.

[ DYES AND PHOTOGRAPHIC EMULSION AND ELEMENTS CONTAINING SAID DYES [75] Inventors: Arthur F umia, Jr.; Donald W.

Heseltine, both of Rochester, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Nov. 23, 1971 [21] Appl. No.: 201,570

Related U.S. Application Data [62] Division of Ser. No. 56,653, July 20, 1970, Pat. No.

[52] U.S. CL... 260/240 D, 96/120, 96/129, 96/142, 260/240 R, 260/268 C, 260/293.65, 260/563 R, 260/3l9.l, 260/326.4

[51] Int, Cl C09b 23/14 [58] Field of Search 260/240 R, 240.9, 240 D [56] References Cited UNITED STATES PATENTS 2,860,982 ll/l958 Jones 260/240 R X [111 3,821,205 [451 June 28, 1974 2,882,158 4/1959 Brooker et al. 260/240 R X 3,652,288 3/1972 Fumia et al. 260/240 R X OTHER PUBLICATIONS Hamer, The Cyanine Dyes and Related Compounds, pages 400, 436 and 603604, Interscience Publishers,

Primary Examiner.1ohn D. Randolph Attorney, Agent, or Firm-R. W. Hampton; M. R.

Chipaloski 5 7 ABSTRACT- 7 Claims, No Drawings DYES AND PHOTOGRAPHIC EMULSION AND ELEMENTS CONTAINING SAID DYES This is a division, of application Ser. No. 56,653 filed July 20, 1970 now US. Pat. No. 3,652,288 issued March 28, 1972.

This invention relates to novel cyanine dyes, and more particularly to dyes with a partially cyclized polymethine bridge derived from enamines containing a cyclohexene ring, and to photographic materials, particularly spectrally sensitized photographic silver halide emulsions and photographic elements, prepared therewith.

It is well known that dyes of the cyanine class sensitize photographic silver halide emulsions. However, this class includes whole groups which have no sensitizing properties or which even have a desensitizing effect. The number of sensitizers that can be used in practice is further limited by inability in many cases to meet the strict requirements of the photographic art as to clearness and storage ability, as well as freedom from fogging, in photographic layers and elements prepared with such sensitizers. Furthermore, the gradation in both the fresh and in the aged condition must have the required value and mustnot change. These requirements are especially applicable to sensitizers for color photographic processes, which in addition need to have a particularly high sensitizing action and also a special selectivity.

We have now found that certain enamines containing a cyclohexene ring having a reactive methylene or methyl substituent thereon give polymethine dyes having a partially cyclized polymethine bridge, that fully satisfy the above mentioned requirements of an advantageous and effective spectral sensitizer, and thus provide a new class of excellent spectral sensitizers for photographic silver halide emulsions. These new dyes sensitize such emulsions up to wavelengths ranging about from 550 to 770 mu, with maximum sensitivities ranging about from 525 to 745 mu. Thus, many of our new polymethine dyes have proven to be excellent sensitizers for the red to near infrared regions of the spectrum. ln general, the dyes of the invention cause only very low fog level in emulsions, both fresh and on incubation. A particularly effective and useful dye compound of our invention is that of Example 9 herein, namely, 4-[3-(5,5dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene) propenyl]- l -ethylquinolinium perchlorate, including other salt compounds thereof, and is the preferred species.

'It is, accordingly, an object of our invention to provide a new class of polymethine dyes that function as spectral sensitizers in photographic silver halide emulsions. Another object is to provide novel light absorbing dyes that are useful in photographic filter layers. Another object is to provide novel photographic elements prepared with our new class of dyes. A further object is to provide means for preparing these new dyes and novel photographic materials of the invention; Other objects will become apparent from aconsideration of the general description and the appended claims.

The new polymethine dyes of our invention are in the form of their quaternary (acid anion) salts and include a symmetrical dye represented by the following general formula:

an unsymmetrical dye represented by the following general formula:

and a styryl dye represented by the following general formula:

wherein d and m each represents a positive integer of from 1 to 2, Q represents the atoms necessary to complete a cyclohexene ring, R represents an alkyl group, preferably a lower alkyl group containing from 1 to 4 carbon atoms, e. g., methyl, ethyl, propyl, isopropyl, bu-

tyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl,

w-sulfobutyl, etc., a sulfatoalkyl group, e.g., fi-sulfatoethyl, 'y-sulfatopropyl, y-sulfatobutyl, w-sulfatobutyl, etc., an alkanoyloxyalkyl group, e.g., B-acetoxyethyl, B-propionyl-oxyethyl, B-butyryloxyethyl, y-acetoxypropyl, w-acetoxybutyl, w-propionyloxybutyl, w-butyryloxybutyl, etc., an alkoxycarbonyl-alkyl group, e.g., B-methoxycarbonylethyl, fl-ethoxycarbonethyl, B-propoxycarbonylethyl, B-butoxycarbonylethyl, 'y-methoxycarbonyl-propyl, 'y-ethoxycarbonylpropyl, w-methoxycarbonylbutyl, w-ethoxycarbonylbutyl, w-butoxycarbonylbutyl, etc., an ally] group, an aralkyl group, e.g., benzyl, phenethyl, etc., or an aryl group, e.g., phenyl, o-tolyl, m-tolyl, p-tolyl, xylyl, ochlorophenyl, m-chlorophenyl, p-chlorophenyl, ocarboxyphenyl, m-carboxyphenyl, p-carboxyphenyl, etc., R represents independently a hydrogen atom or a lower alkyl group, e.g., methyl, ethyl, propyl, isopropyl, butyl, etc., R represents independently a lower alkyl group, methyl, ethyl, propyl, isopropyl, butyl, etc., or an aryl group, e.g., phenyl, o-tolyl, m-tolyl, ptolyl, xylyl, o-chlorophenyl, m-chlorophenyl, p-

chlorophenyl, o-carboxyphenyl, m-carboxyphenyl, p-

carboxyphenyl, etc., R, and R collectively, with the nitrogen atom to which they are attached represent the residue of a secondary heterocyclic amine, e.g., lpyrrolidinyl, l-piperidyl, l-indolinyl, R and R each represents an alkyl group, preferably a lower alkyl containing from 1 to 4 carbon atoms, e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, octyl, decyl, dodecyl, etc., X represents an acid anion, e.g., chloride, bromide, iodide, thiocyanate, sulfamate, perchlorate, benzenesulfonate, p-toluenesulfonate, methyl sulfate, ethyl sulfate, etc., and Z represents the nonmetallic atoms necessary to complete a 5- to 6-membered heterocyclic nucleus selected from the group consisting of a thiazole nucleus (e.g., thiazole, 4-methylthiazole, 4- phenylthiazole, S-methylthiazole, S-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4-(2- thienyl)thiazole, etc.); a benzothiazole nucleus (e.g.,

benzothiazole, 4-chlorobenzothiazole, 5- chlorobenzothiazole, 6-chlorobenzothiazole, 7- chlorobenzothiazole, 4-methylbenzothiazole, 5- methylbenzothiazole, 6-methylbenzothiazole, 5-

bromobenzothiazole, 6-bromobenzothiazole, 4-phenylbenzothiazole, S-phenylbenzothiazole,

4-methoxybenzothiazole, S-methoxybenzothiazole, 6- methoxybenzothiazole, 5-iodobenzothiazole, .6- iodobenzothiazole, 4-ethoxybenzothiazole, 5- ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-dioxymethylenebenzothiazole, S-hydroxybenzothiazole, 6- hydroxybenzothiazole, etc. a naphthothiazole nucleus e.g., til-naphthothiazole, B-naphthothiazole, 5-methoxy-B-naphthothiazole, 5-ethoxy-B- naphthothiazole, 8-methoxy-a-naphthothiazole, 7-methoxy-a-naphthothiazole, etc. a

thianaphtheno-7', 6',4,5-thiazole nucleus (e.g., 4'- methoxythianaphtheno-7-6',4,5-thiazole, etc.); an oxazole nucleus (e.g., 4-methyl-oxazole, 5- methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, S-phenyloxazole, etc.); benzoxazole nucleus (e.g., benzoxazole, 5- chlorobenzoxazole, S-methylbenzoxazole, 5- phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, I 5- methoxybenzoxazole, S-ethoxybenzoxazole, 6- chlorobenzoxazole, -methoxybenzoxazole, 5-

hydroxybenzoxazole, o-hydroxybenzoxazole, etc.); a naphthoxazole nucleus (e. g., a-naphthoxazole, ,B-naphthoxazole, etc.); a selenazole nucleus (e.g., 4- methylselenazole, 4-phenylselenazole, etc.); a benzoselenazole nucleus (e. g., benzoselenazole, 5- chlorobenzoselenazole, S-methoxybenzoselenazole, 5 -hydroxybe nzoselenazole, tetrahydrobenzoselenazole, etc.); a naphthoselenazole nucleus (e.g., a-naphthoselenazole, ,B-naphthoselenzaole, etc. a thiazoline nucleus (e.g., thiazoline 4 methylthiazoline, etc.); a 2-quinoline nucleus (e.g.,

quinoline, 3-methylquinoline, S-methylquinoline, 7-

methylquinoline, 8-methylquinoline, 6- chloroquinoline, S-chloroquinoline, 6- methoxyquinoline, o-ethoxyquinoline, 6-

4 chloropyridine, 3-hydroxypyridine, 3-phenylpyridine, etc.); a 4-pyridine nucleus (e.g., Z-methylpyridine, 3- methylpyridine, 3-chloropyridine, 2,6- dimethylpyridine, 3-hydroxypyridine, etc.); a lalkylimidazole nucleus (e.g., l-methylimidazole, 1-ethyl-4-phenyl-imidazole, lbutyl-4 ,5-' dimethylimidazole, etc.); a l-alkyl-benzimidazole nucleus (e.g., l-methylbenzimidazole, l-butyl-4- methylbenzimidazole, l-ethyl-5,6- dichlorobenzimidazole, etc. and a lalkylnaphthimidazole nucleus (e.g., l-ethyl-anaphthimidazole, l-methyl-B-naphthimidazole, etc.

The new polymethine dyes of the invention can be conveniently prepared in a number of ways. For example, the symmetrical dyes of Formula I above are prepared to advantage by heating a mixture of an enamine compound of the formula:

wherein 0, R and R are as previously defined with (a) a dialkoxymethyl acetate, e.g., diethoxymethyl acetate, to form the dye compounds wherein m is l,'or with (b) ,B-anilinoacroleinanil hydrochloride, to form the dye compounds wherein m is 2, in the proportions of about 2 moles of the enamine to each mole of (a) or (b), as illustrated by Examples 3 and 4 herein.

The unsymmetrical polymethine dyes of Formula ll above are prepared by heating a mixture of a compound of Formula lV above with a compound of the formula:

wherein d, R, X and Z are as previously defined, and A represents the group CH=CH .NR.RG wherein q representsa positive integer of from 1 to 2, R represents a hydrogen atom or an acyl group, e.g., acetyl, propionyl, butyryl, benzoyl, etc., and R represents an aryl group, e.g., phenyl, tolyl, etc., in about equimolar proportions, as illustrated by Examples l, 2, 4-9 and other examples herein.

The styryl dyes of Formula Ill above are prepared by heating a compound of Formulas IV or V with an aryl aldehyde of the formula:

VI. Ra

wherein R and R are as previously defined, and wherein g represents a positive integer of from 1 to 2 in approximately equimolar proportions, as illustrated by Example 10 herein.

Adevantageously, the reaction mixtures are heated in an inert solvent medium such as N,N- dimethylacetamide, a lower alkanol such as ethanol, acetic anhydride, etc., or in mixtures thereof and, if desired, in the presence of a basic condensing agent such as a trialkylamine, e.g., triethylamine, tripropylamine, triisopropylamine, etc., N,N-dialkylanilines such as N,N-dimethylaniline, etc., N-alkylpiperidines such as N-methylpipe-ridine, etc., and the like. Preferably the reactions are carried out at refluxing temperatures of the reaction mixtures. On chilling or by addition of a nonsolvent, or both, the dye compounds separate from the mixtures and are purified by one or more recrystallizations with appropriate solvents. The reactants can be employed, when desirable, with a small excess of one or the other, i.e., greater than the stoichiometrically calculated equivalents. The preparation of certain cyclohexene compounds coming under Formula IV are described hereinafter. The heterocyclic intermediates represented by Formula V, as well as the aryl aldehydes of Formula Vl, are well known substances, and methods for preparing these compounds are well known to the art.

3-Methyl-2-cyclohexene-l-one compounds which can be used in the preparation of the enamine compounds having the formula IV include 3 ,5-dimethyl-2-cyclohexenel .-one

3 ,4 ,6-trimethyl-5 -hydrox y-Z-cyclohexenei -one.

3 ,5 ,5-trimethyl-6-methoxy-2-cyclohexene- 1 -one 3-methyl-2-cyclohexene- I -one 3-methyl-5 -benzoyl-2-cyclohexene- 1 -one 3 ,4-dimethyl-2-cyclohexene- 1 -one 3,5-dimethyl-6-phenyl-2-cyclohexene- 1 -one 3,6-dimethyl-5-phenyl-2-cyclohexenel-one 3-methyl-5,6-diphenyl-2-cyclohexenel-one 3,5,5,6-tetramethyl-Z-cyclohexene- 1 -one 3,5,5-trimethyl-6-phenyl-2-cyclohexene-l-one, for

example. The preparation of a number of 3-methyl-2- cyclohexene-l-one compounds is disclosed in German patent 1,088,949; Bull. Soc. Chim. France, pages 96-8 (1962) and J.A.C.S. Vol. 84, pages 2625-28 (1962), for example. The manner in which 3-methyl-2- cyclohexene-l-one compounds can be used to prepare the enamine compounds having the formula IV is illustrated in Examples l8, l9 and 20, hereinafter.

The following examples further illustrate the new polymethine dyes and novel photographic materials of the invention.

EXAMPLE 1 2-[ 3-( 6-Ethoxycarbonyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl]-3-ethy1benzoxazolium perchlorate I-(4-Ethoxycarbonyl-3-methyl-Z-cyclohexen-l- 6O CHPCH, H2O

melted at l24-l25C. with decomposition were obtained.

EXAMPLE 2 2-[ 3-( 6-Ethoxycarbonyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl]-3-ethylbenzothiazolium perchlorate l-( 4-Ethoxycarbonyl-3-methy1-2-cyclohexenl ylidene pyrrolidinium perchlorate (3.7 g.), 2-(2- Acetanilidovinyl)-3-ethylbenzothiazolium iodide (4.5 g.), ethanol (25 ml.) and triethylamine (1.5 ml.) were placed in a flask and heated at reflux, with stirring, for 10 minutes. The reaction mixture was then chilled and the crude dye which precipitated was collected on a filter and then purified by recrystallizing once from methanol. 3.2 Grams (62 percent) of dye were thus obtained. The 3.2 grams of dye were redissolved in the methanol recrystallization liquors and the resulting solution was filtered through a bed of Norite. The filtrate was then brought to a boil and filtered. After chilling, the dye which precipitated was collected on a filter and dried. The yield of purified dye was 2.7 grams (52 percent), melting at 203204C. with decomposition.

EXAMPLE 3 N- 5,5-dimethyl-3-N-pyrrolidinyl-2- cyclohex'enylidene )propenyl ]-2-cyclohexenylidene pyrrolidinium perchlorate mo on. [no our \C/ O/ calon, 1120 cm 1110 cHi CHr-C N- o=cHoH=oH-o (3:N4 H:CH/1 c 0 cHi-cn,

5,5-Dimethyl-3-methylenel l-pyrrolidinyl lcyclohexene (1.9 g., 2 mols) and diethoxymethyl acetate (6.4 g., 1 mol. excess) were dissolved in N,N- dimethylacetamide (10 ml.) and heated on a steam bath for 20 min. A hot aqueous solution 10 ml.) of sodium perchlorate (2.4 g.) was added and the reaction allowed to heat on the steam bath an additional five minutes. The mixture was chilled, the crude product filtered, rinsed with ethanol and dried. After two recrystallizations from methanol, the yield of purified dye was 0.8 g. (32 percent), m.p. 2 l 72l8 C. with decomposition.

EXAMPLE 4 N-{5,5-Dimethyl-3-[5-(5,5edimethyl-3-N-pyrrolidinyl-Z-cyclohexenylidene)-1,3-pentadienyl1-2- cyclohexenylidene} pyrrolidinium perchlorate on; A

Hz-C 2 C CHi-GHI B-Anilinoacroleinanil hydrochloride (2.6 g., 1 mol.) and 5,5 dimethyl-3-methylenel l-pyrrolidinyl)- l cyclohexene (5.7 g., 2 mols. 50 percent excess) were dissolved in acetic anhydride (15 ml.) and stirred at room temperature until the initial heat of reaction had subsided. The mixture was then heated on a steam bath for 20 minutes, cooled to room temperature, and then an aqueous solution (10 ml.) of sodium perchlorate (2.4 g.) was added with stirring. The crude product was precipitated by the addition of ether (100 ml.) with stirring. After chilling, the crude dye was filtered, washed with water and dried. After two recrystallizations from ethanol, the yield or purified dye was 0.4 g. (8 percent), m.p. l9ll94 C. dec.

EXAMPLE 5 EXAMPLE 6 2-[ 3-( 5 ,5-Dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene )propenyl]-3-ethylbenzothiazolium 2-(2 Acetanilidovinyl)-3-ethylbenzothiazolium iodide (4.5 g., 1 mol.) and 5,5-dimethyl-3-methylene-l- (l-pyrrolidinyl)-l-cyclohexene (1.9 g., 1 mol.) were dissolved in ethanol (20 ml.) and heated under reflux for five minutes. After chilling, the crude product was collected and dried. After two recrystallizations from methanol, the yield of purified dye was 2.3 g. (45 percent), m.p. 277-278 C. dec.

EXAMPLE 7 2-[ 3-( 5,5-Dimethyl-3-N-pyrrolidinyl-Z- cyclohexenylidene)propenyll-3H-indolium iodide.

2-( 2-Acetanilidovinyl l ,3,3-trimethyl-3H-indolium iodide (4.5 g., 1 mol.) and 5,S-dimethyI-S-methylenel-(1-pyrrolidinyl)-l-cyclohexene (1.9 g., 1 mol.) were dissolved in ethanol 20 ml.) and heated under reflux for ten minutes. After chilling, the crude product was filtered and dried. After two recrystallizations from ethanol, the yield of purified dye was 2.6 g. (52 percent), m.p. 230-23l C. dec.

EXAMPLE 8 2-[3-(5,5-Dimethyl 3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl]-1 ethylnaphtho[ 1 ,2- d]thiazolium iodide 2-( 2-Anilinovinyl)- 1 -ethylnaphtho[ 1,2-d]thiazolium p-toluenesulfonate (5.0 g., 1 mol.) was mixed with ethanol 20 ml.). To this mixture was added acetic anhydride (0.6 ml., 1 mol. 10 percent), triethylamine 1.5 ml., 1 mol. 10 percent) and 5,5-dimethyl-3- methylene-Hl-pyrrolidinyl)-l-cyclohexene (1.9 g., 1 mol.) in that order. The resulting mixture was heated under reflux for ten minutes. To the hot reaction mixture, a hot aqueous solution of sodium iodide (2.0 g.) was added with stirring. After chilling, the crude product was filtered and dried. After two recrystallizations from methanol, the yield of purified dye was 0.4 g. (7 percent), m.p. 252-253 C. dec.

EXAMPLE 9 4-[ 3-( 5 ,5 -Dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propeny1]-l-ethylquinolinium perchlorate 4-(2-Anilinovinyl)-l-ethylquinolinium iodide (4.01 1 mol.) was mixed with ethanol (20ml.). To this mixture was added acetic anhydride (0.6 ml., 1 mol. l0 percent), triethylamine (1.5 ml., 1 mol. 10 percent) and 5,5-dimethyl-3-methylenel l-pyrrolidinyl l cyelohexene 1.9 g., 1 mol.) in that order. The resulting mixture was heated under reflux for twenty minutes. To the warm reaction mixture, an aqueous solution (10 ml.) of sodium perchlorate (1.8 g.) was added. After chilling, a sticky solid separated. Ethanol 175 ml.) was added with stirring and crystalline crude product was obtained. The crude dye was collected and dried. After two recrystallizations from methanol, the yield of purified dye was 0.8 g. (17 percent), m.p. 213214 C. dec.

EXAMPLE 10 1-(5,5-Dimethyl-3-p-dimethylaminostyryl-2- cyclohexenylidene)pyrrolidinium perchlorate p-Dimethylaminobenzaldehyde (1.5 g., 1 mol.) and 5,5-dimethyl-3-methylenel-( l-pyrrolidinyl)-1- cyclohexene (1.9 g., 1 mol.) were dissolved in ethanol and heated under reflux for several minutes. 50 percent Hydroiodic acid (3.2 g., 1 mol. 20 percent) was added and the mixture heated under reflux for an additional twenty minutes. A hot aqueous solution (5 ml.) of sodium perchlorate 1.8 g.) was added.) After chilling, the crude product was filtered and dried. After two recrystallizations from acetic acid, the yield of purified dye was 0.4 g. percent), m.p. 262263 C. dec.

EXAMPLE 1 l 2-[ 3-( 6-Ethoxycarbonyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl1-l-ethylnaphtho dlthiazolium perchlorate CHz-CH:

once from about 750 ml. of methanol, discarding some solid that did not dissolve. 1.8 Grams (32 percent) of purified dye which melted at 2l7-2l 8C. with decomposition were obtained.

EXAMPLE 12 5 ml.) were placed in a flask and heated at reflux for 10 minutes. The reaction mixture was then chilled and the crude dye which precipitated was collected on a filter, rinsed with methanol and dried to obtain 2.6 g. (89 percent) of crude dye. The crude dye thus obtained was dissolved in cresol and methanol was added to precipitate the dye 1.9 g., 65 percent). The dye thus obtained was dissolved in cresol and methanol was added to precipitate the dye, which was extracted with hot methanol. 1.6 Grams (55 percent) of dye remained and was again extracted with about 150 m1. of hot methanol to obtain 1.3 g. (45' percent) of purified dye melting at 25 8259C. with decomposition.

EXAMPLE 13 4-[ 3-( 5,5-Dimethyl-3-N-indolinyl-2- cyclohexenylidene)propenyl]-l-ethylquinolinium perchlorate v 4-(2-Anilinovinyl)-l-ethylquinolinium iodide (2.0 g), '1,5,5-trimethy1cyclohexen-3-ylidene indolinium perchlorate (1.7g), acetic anhydride (0.5 ml), triethylamine (l.5 ml), and ethanol (25 ml) were placed'in a flask and heated at reflux for 20 minutes. Upon chilling the reaction mixture tar along with some crystals came out. The reaction mixture was heated to reflux, stirred and scratched, allowed to cool slowly and then filtered, rinsed with methanol and dried. Weight 1.1 g (42 percent). Upon recrystallization from ml of methanol 0.5 g (19 percent) of dye was obtained. A further recrystallization from 100 ml of methanol gave 0.3 g (12 percent) of dye melting at 21 1-2l2C with decomposition.

EXAMPLE 14 2-[3-(5,5-Dimethyl-3-N-indolinyl-2- cyclohexenylidene)propenyl]-3-ethylbenzoxazolium perchlorate I 2-( 2-Acetanilidovinyl )-3-ethylbenzoxazolium iodide (2.2 g.), l,5,S-trimethylcyclohexen-3-ylidene indolinium perchlorate (1.2 g.), ethanol (25 m1.) and triethylamine (0.8 ml.) were placed in a flask and heated at reflux for 10 minutes. The reaction mixture was then chilled and the crude dye which precipitated was collected on a filter, rinsed with methanol and dried to obtain 1.8 g. (69 percent) of dye. Upon recrystallization from 250 ml. of methanol (0.8 g.) and further recrystallization from ml. of methanol 0.4 g. (16 percent) 2[ 3-( 5,S-Dimethyl-3-piperidino-2- cylohexenylidene)propenyl]-3-ethylbenzoxazolium perchlorate 5,5-Dimethyl-3-methylene-1-( 1-piperidyl)-lcyclohexene (5.84 g., 1 mol. 180 percent) and 2-,B- acetanilidovinyl-3-ethylbenzoxazolium iodide (4.36 g., 1 mol.) were mixed in ethanol ml.) and heated under reflux for thirty minutes. The mixture was then poured with stirring into a solution of sodium perchlorate (5 g.) in water (100 ml.). After chilling overnight, the crude dye was collected on a filter, washed with water and methanol and dried. After two recrystallizations from methanol, the yield of pure dye was 1.98

g. (41 percent), m.p. I634C. dec.

In place of the Z-B-acetanilidovinyl-3-ethylbenzoxazolium iodide in Example 15, there can be substituted any other of the mentioned quaternary salts coming 12 3,3-dimethyl-3H-indolium quaternary salts (e.g., the chloride, bromide, iodide, perchlorate, benzenesulfonate, p-toluenesulfonate, methyl sulfate. etc. salt), or with a 2-(2-anilinovinyl)-l-alkyl (e.g., methyl. ethyl, propyl, isopropyl, butyl, etc.) napththo [l,2' dlthiazolium quaternary salt (e.g., the chloride, bromid'e, iodide, perchlorate, p-toluenesulfonate, methyl sulfate, etc. salt), and the like, to give with the 5,5- dimethyl-3-methylenel 1-piperidyl)-l-cyclohexene the corresponding polymethine dye compounds having generally similar utility as sensitizers for photographic silver halide emulsions. Illustrative examples include 2-[ 3-( 5,5 dimethyl-3-piperidino-2- cyclohexenylidene )propenyl ]-3-ethyl-benzothiazolium perchlorate; 2-[ 3-( 5,5-dimethyl-3-piperidino-2- cyclohexenylidene )propenyl l ,3,3-trimethyl-3H- indolium iodide; 2-[3-(5,5-dimethyl-3-piperidino-2- cyclohexenylidene) propenyl l-ethylnaphtho[ 1,2- dlthiazolium iodide; and the like.

The dyes of the above examples were tested in a silver bromoiodide emulsion containing 0.77 mole percent iodide of the type described by Trivelli and Smith, Phot. Journal, 79, 330 (1939). The dyes, dissolved in suitable solvents, were added to separate portions of the emulsions at the concentrations indicated. After digestion at C. for 10 minutes, the emulsions were coated at a coverage of 432 mg. of silver/ft on a cellulose acetate film support. A sample of each coating was exposed on an Eastman IB Sensitometer and to a wedge spectrograph, processed for three minutes in a developer of the following composition:

Developer N-methyl-p-aminophenol sulfate 2.0 g. Sodium sulfite (anhydrous) 90.0 g. Hydroquinone 8.0 g. Sodium carbonate (monohydrate) 52.5 g. Potassium bromide 5.0 3. Water to make 1.0 liter and then fixed, washed and dried. The sensitizing values obtained are shown in the following Table 1.

Table l Dye Concen- Sensitization Dye of tration (g./ Type of Sensitization Maximum Example No. mole Silver) Emulsion Range (mu) (mu) 1 0.20 g. Bromoiodide to 650 610 2 0.10 g. Bromoiodide to 690 650 3 0.04 g. Bromoiodide to 760 710 4 0.10 g. Bromoiodide 5 0.04 g. Bromoiodide to 660 600 6 0.04 g. Bromoiodide to 710 640 7 0.04 g. Bromoiodide to 660 620 8 0.04 g. Bromoiodide to 750 675 9 0.04 g. Bromoiodide to 770 725 l0 0.04 g. Bromoiodide to 670 575 l l 0.20 g. Bromoiodide to 710 670 12 0.02 g. Bromoiodide to 750 720 13 0.02 g. Bromoiodide to 770 745 14 0.02 g. Bromoiodide to 690 655 15 0.04 g. Bromoiodide to 650 615 EXAMPLE 16 2- 3-[5,5-Dimethyl-3-( 4-ethoxycarbonyll piperazinyl)-2-cyclohexenylidene]propenyl} -3-ethylbenzothiazolium perchlorate 5,5-Dimethyl-3-methylene-1-(4-ethoxycarbonyl-lpiperazinyl)-1-cyclohexene (3.0 g) and 2-(2- acetanilidovinyl)-3-ethylbenzothiazolium iodide (4.5 g) were dissolved in ethanol (25 m1)-and heated at reflux for minutes and then an aqueous solution (5.0 ml) of NaClO, was added. The crude dye was collected on a filter and recrystallized twice from methanol. The still impure dye (3.16 g) was dissolved in chloroform (200 ml) at room'temperature and the solution passed through norite. After evaporating to dryness, the yield 5 ,5-Dimethyl-3-methylenel 4-ethoxycarbonyl- 1 piperazinyl)-l-cyclohexene (3.0 g) and 2-(2- acetanilidovinyl)-3-ethylbenzoxazolium iodide (4.34 g) were dissolved in ethanol ml) and heated atreflux for 5 minutes. Aqueous NaClO 1.5 g in 5 ml) was added and. after chilling, the crude dye was collected on a filter. After one recrystallization from methanol, the yield of purified dye was 2.92 (53 percent), m.p. =207208C d.

The following examples illustrate the preparation of certain cyclohexene derivatives employed as intermediates in the preceding dye examples.

EXAMPLE l8 5.5-Dimethyl-3-methylene-l-( l-pyrrolidinyl)- l cyclohexene 3,5,5-Trimethyl-2-cyclohexene-l-one (41.4 g., 1 mol) and pyrrolidine (32.0 g., 1 mol. 50 percent) were dissolved in toluene (90ml) and heated under reflux for four hours in an apparatus designed for the continuous removal of water. The toluene and excess pyrrolidine were then removed by distillation under reduced pressure and the residue distilled under vacuum. 'The yield of product was 40.0 g. percent), b.p. 82-

-83 C./0.2 mm. Hg.

EXAMPLE l9 l,5,S-Trimethyl-3-phenylimin0- 1 -cyclohexene H: C H3 0 1120 CHz Isophorone (27.6 g., 1 mol), aniline (20.5 g., 1 mol. 10 percent) and piperidine (1 ml.) were dissolved in xylene (50 ml.) and heated under reflux for four hours in an apparatus designed for the continuous removal of water. The mixture was distilled under reduced pressure and the fraction boiling l30160 C./ 12mm. was collected as a colorless oil. Yield 36.1 g., 85 percent.

EXAMPLE 20 5,5-Dimethyl-3-methylenel l-piperidyl)- 1 cyclohexene This compound can be prepared in 46 percent yield by the method of above Example 18 by replacing the pyrrolidine with piperidine.

EXAMPLE 21 1-(4-Ethoxycarbonyl-3-methyl-2-cyclohexenl ylidene)-pyrrolidinium perchlorate 54.6 Grams of 4-ethoxycarbonyl-3-methyl-2- cyclohexen-l-one 38.0 ml. of pyrrolidine, ml. of benzene and 0.5 gram of p-toluenesulfonic acid were placed in a apparatus defined for the continuous removal of H 0 and heated at reflux with stirring for 45 minutes. The solvent was removed by evaporation under reduced pressure and the residue obtained was dissolved in about 1200 ml. of ether and the resulting solution was treated with 72 percent perchloric acid with cooling until the reaction mixture was just acid. After chilling the reaction mixture was decanted and the residue obtained was stirred with a fresh 1 liter solution of ether and decanted. The residue obtained was dissolved in boiling ethanol and the solution was filtered while hot and then concentrated to about 250 ml. and cooled. The reaction mixture was then chilled and the desired product which precipitated was collected on a filter and dried. 76.0 Grams (75 percent) of product melting at l02 "-l03C. were obtained.

EXAMPLE 22 1 ,5 ,5-Trimethyl-Z-cyclohexenel -ylidene indolinium perchlorate EXAMPLE 23 5,S-DimethyI-B-methylene-1-(4-ethoxycarbonyl-lpiperazinyl l -cyclohexene H3O CH3 \C/ H H 1110 on, o -c 0 H: 7 N N-C c o-o 00,115

H H1 H2 I 3,5,5 Trimethyl-2-cyclohexen- I -one (4 l .4 g),

.l-ethoxycarbonylpiperazine (60.0 g), p-toluenesulfonic acid (0.5 g), and toluene (90 ml) were placed in an apparatus designed for the continuous removal of water and heated at reflux for 8 hours. After removal of solvent, the residue was distilled in vacuum to obtain solved in suitable'solvents, were added to separate portions of the emulsion at the concentrations indicated. After digestion at 52C for 10 minutes, the emulsions were coated at a coverage of 432 mg Ag/ft on a cellulose acetate film support. A sample of each'coating was exposed on an Eastman 1B Sensitometer andto a wedge spectrograph, processed for 3 minutes in Kodak Developer D-l9, fixed, washed and dried.

The dyes of Examples 1, 2, l l, 16 and 17 weretested in a 2.5 percent iodide silver bromoiodide emulsions with uniform cubic grains of 0.2 pm grain size. The emulsion samples were coated at 100 mg Ag/ft and 694g gelatin/ft on a cellulosev acetate film support. The film was exposed to a wedge spectrograph in an Eastman lB Sensitometer, processed for 6 minutes in Kodak Rapid X-ray Developer, fixed, washed and dried.

Other polymethine dyes of the invention having generally similar photographic sensitizing properties and applications and coming under the definitions of Formulas I, II, and Ill above, can be prepared in accordance with the procedures of the preceding Examples 1 to 17 by appropriate selection of intermediates from those defined by above Formulas IV to VII.

In the preparation of photographic emulsions, the new dyes of the invention are advantageously incorporated in the finished silver halide emulsion and should, of course, be uniformly distributed throughout the emulsion. The methods of incorporating dyes in emulsions are relatively simple and well known to those skilled in the art of emulsion making. For example, it is convenient to add the dyes from solutions in appropriate solvents, in which the solvent selected should have no deleterious effect on the ultimate lightsensitive materials. Methanol, isopropanol, pyridine, etc., alone or in combination have proven satisfactory as solvents for the majority of our new dyes. The type of silver halide emulsions that are desensitized with our I dyes include any of those prepared with hydrophilic prepared with hydrophilic colloids, such as, natural materials, e. g., gelatin, albumin, agar-agar, gumarabic, alginic acid, etc., and synthetic hydrophilic resins, e.g., polyvinyl alcohol, polyvinyl pyrrolidone, cellulose ethers, partially hydrolyzed cellulose acetate, and the like.

The concentration of our new dyes in the emulsion can be widely varied, i.e., generally from about 5 to about 100 mg. perliter of flowable emulsion. The specific concentration will vary according to the typeof light-sensitive material in the emulsion and according to the effects desired. The most advantageous dye concentration for any given emulsion can be readily deter- 46.6 g (56 percent), b.p. =l45-l53C/0.1 mm Hg. mined by making the tests and observations cus- Table 2 Dye Concen- Sensitiza- Sensitization Dye of tration (g./ Type of tion Range Maximum Example No. mole Silver) Emulsion (mu) (mu) I6 .30 Bromoiodide to 690 660 I7 .30 Bromoiodide to 650 6l5 The dyes of Examples 12-14, like Examples 3-10 and 15, were tested in a silver bromoiodide emulsion containing 0.77 mole percent iodide. The dyes, distomairly used in the art of emulsion making. .The emulsions are coated to advantage on any of the support materials used for photographic elements, for example,

propionate, cellulose nitrate, polystyrene, polyesters, polyamides, etc.

To prepare a gelatino-silver halide emulsion sensitized with one of the new dyes, the following procedure is satisfactory: A quantity of the dye is dissolved in a suitable solvent and a volume of this solution containing from to 100 mgs. of dye is slowly added to about 1000 cc. of a gelatino-silver halide emulsion. With most of the new dyes, to mgs. of dye per liter of emulsion suffice to produce the maximum sensitizing effect with 'the ordinary gelatino-silver halides including silver chloride, bromide, bromoiodide, chlorobromide, chlorobromoiodide, etc. emulsions. With fine-grain emulsions, which include most of the ordinary employed gelatino-silver chloride emulsions and the like, somewhat larger concentrations of dye may be necessary to secure optimum sensitizing effect. While the preceding has. dealt with emulsions comprising gelatin, it will be understood that these remarks apply generally to any emulsions wherein part or all of the gelatin is substituted by another suitable hydrophilic colloid such as mentioned above.

The above statements are only illustrative and are not to be understood as limiting the invention in any sense, as it will be apparent that the new dyes can be incorpo-' rated by other methods in many of the photographic silver halide emulsions customarily employed in the art. For instance, the dyes can be incorporated by bathing a plate or film upon which an emulsion has been coated, in the solution of the dye in an appropriate solvent. Bathing methods, however, are not to be preferred ordinarily.

Photographic silver halide emulsions, such as those listed above, containing the sensitizing dyes of my invention can also contain such addenda as chemical sensitizers, e.g., sulfur sensitizers (e.g., allyl thiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), various gold compounds (e. g., potassium chloroaurate, auric trichloride, etc.) (see U.S. Patents to W. D. Baldsiefen 2,540,085, granted Feb. 6, 1951; R. E. Damschroder 2,597,856, granted May 27, 1952, and H. C. Yutzy et a1 2,597,915, granted May 27, 1952), various palladium compounds, such as palladium chloride (W. D. Baldsiefen U.S. 2,540,086, granted Feb. 6, 1951 potassium chloropalladate (R. E. Stauffer. et al. U.S.

Pat. No. 2,598,079, granted May 27, 1952), etc., or mixture of such sensitizers; antifoggants, such as ammonium chloroplatinate (A. P. H. Trivelli et a1 U.S. 2,566,245, granted Aug. 28, 1951 ammonium chloroplatinite (A.P.H. Trivelli et al U.S. Pat. No. 2,566,263, granted Aug. 28, I951), benzotriazole, nitrobenzimidazole, S-nitrolindazole, benzidine, mercaptans, etc. (see Mees, The Theory of the Photographic Process", Macmillan Pub., 1942, page 460), or mixtures thereof; hardeners, such as formaldehyde (A. Miller U.S. Pat. No. 1,763,533, granted June 10, 1930), chrome alum (U.S. Pat. No. 1,763,533), glyoxal (.l. Brunken U.S.

Pat. No. 1,870,354, granted Aug. 9, 1932, dibromacrolein (0. Block et al. British 406,750, accepted Mar.

8, 1934), etc.; color couplers, such as those described in 1. F. Salminen et a1. U.S. Pat. No. 2,423,730, granted July 7, 1947, Spence and Carroll U.S. Pat No. 2,640,776, issued .lune2, 1953, etc.; or mixtures of such addenda. Dispersing agents for color couplers, such as those set forth in U.S. Pat. Nos. to E. E. Jelley et al. 2,322,027, granted June 15, 1943, and L. D.

18 Mannes et al. 2,304,940, granted Dec. 15, 1942, can also be employed in the above-described emulsions. The dyes of this invention can be supersensitized with a sulfonated polynuclear aromatic supersensitizer, such as the supersensitizers described in Jones U.S. Pat. No. 2,947,630, issued Aug. 2, 1960, cold-6, e.g., Calcolfluor White MR (a bis[s-triazin-Z-ylamino]stilbeneadded to emulsions supersensitized as described above,

to reduce fog.

The dyes of this invention have higher speed in the spectrally-sensitized region than the somewhat related dyes of Belgian Patent 674,800. Further, the dyes of this invention can be made without contamination by the bis dyes.

The dyes of this invention can be advantageously incorporated in print-out emulsions to improve the photographic properties of these emulsions. In one instance, dyes according to this invention can be used to improve the photographic properties of a radiationsensitive silver halide emulsion comprising silver halide grains having polyvalent ions occluded therein, wherein said emulsion contains a halogen acceptor and which can optionally contain a stabilizer precursor.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. A polymethine dye selected from the group consisting of a symmetrical dyerepresented by the following general formula:

an unsymmetrical dye represented by the following general formula:

and a styryl dye represented by the following general formula:

wherein d and m each represents a positive integer of from l to 2, Q represents the atoms necessary to complete a cyclohexene ring, R represents atmember selected from the group consisting of an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, a carboxyalkyl group, a sulfoalkyl group, a sulfatoalkyl group, an alkanoyloxyalkyl group, an alkoxycarbonylalkyl group, allyl, an aralkyl group and a monocyclic aryl nucleus containing 6 nuclear carbon atoms, R, represents independently a member selected from the group consisting of a hydrogen atom and a lower alkyl group, R represents independently a member selected from the group consisting of a lower alkyl group and a monocyclic aryl nucleus containing 6 nuclear carbon atoms, R, and R collectively, with the nitrogen atom to which they are attached represent the residue of a secondary heterocyclic amine, R and R each represents an alkyl group, X represents an acid anion, and Z represents the nonmetallic atoms required to complete a 5- to 6- membered heterocyclic nucleus selected from the class consisting of a thiazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a thianaphtheno- 7',6,4,5-thiazole nucleus, an oxazole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a selenazole nucleus, a benzoselenazole nucleus, a naphthoselenazole nucleus, a thiazoline nucleus, a Z-pyridine nucleus, a 4-pyridine nucleus, a 2-quinoline nucleus, a 4- quinoline nucleus, a l-isoquinoline nucleus, a 3- isoquinoline nucleus, a 3,3-dialkylindolenine nucleus, an imidazole nucleus, a benzimidazole nucleus, and a naphthimidazole nucleus.

2. A polymethine dye in accordance with claim I having the formula I of claim 1.

3. A polymethine dye in accordance with claim 1 having the formula II of claim 1.

4. A polymethine dye in accordance with claim I having the formula III of claim 1.

5. A polymethine dye selected from, the dye compounds consisting ofv 2-. l 3-[ 6-ethoxycarbonyl-3'( 1-pyrrolidinyl)-2- cyclohexenylidene]propenyl -3-ethylbenzoxazolium acid anion salt, 2-

3-[6-ethoxycarbonyl-3-( l-pyrrolidinyl)-2- cyclohexenylidene]propenyl ,3-ethylbenzothiazolium acid anion salt, 2-[3-(5,5-dimethyl-3-N-pyrrolidinyl-Z- cyclohexenylidene)propenyl]-3-ethylbenzoxazolium acid anion salt, 2-[3-(5,5-dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl]-3-ethylbenzothiazolium acid anion salt, 2-[3-(5,5-dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl] -3H-indolium acid anion salt, 2-[3-(5,5-dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene )propenyl l -ethylnaphtho[ l ,2- d]thiazolium acid anion salt, 4-[3-(5,5-dimethyl-3-N- pyrrolidinyl-2-cyclohexenylidene )propenyl l ethylquinolinium acid anion salt, 3-[6-ethoxycarbonyl-3-(N-pyrrolidinyl)-2- cyclohexenylidene]propenyl l -l-ethylnaphtho-[l,2-d]thiazolium acid anion salt and 4-[ 3-( 5 ,S-dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl 1 -ethylquinolinium perchlorate.

6. A polymethine dye selected from the dye compounds consisting of N- 5,5-dimethyl-3-[3-(5,5- dimethyl-3-N-pyrrolidinyl-2- cyclohexenylidene)propenyl]-2-cyclohexenylidene pyrrolidinium acid anion salt, and N- 5,5-dimethyl-3-[5-(5,5-dimethyl-3-N pyrrolidinyl-2- cyclohexenylidene)-l ,3-pentadienyl1-2- cyclohexenylidene }-pyrrolidinium acid anion salt.

7. The polymethine dye l-(5,5-dimethyl-3-pdimethylaminostyryl-2-cyclohexenylidene)pyrrolidinium acid anion salt. 

2. A polymethine dye in accordance with claim 1 having the formula I of claim
 1. 3. A polymethine dye in accordance with claim 1 having the formula II of claim
 1. 4. A polymethine dye in accordance with claim 1 having the formula III of claim
 1. 5. A polymethine dye selected from the dye compounds consisting of 2-(3-(6-ethoxycarbonyl-3-(1-pyrrolidinyl)-2-cyclohexenylidene)propenyl)-3 -ethylbenzoxazolium acid anion salt, 2-(3-(6-ethoxycarbonyl-3-(1-pyrrolidinyl)-2-cyclohexenylidene)propenyl)-3 -ethylbenzothiazolium acid anion salt, 2-(3-(5,5-dimethyl-3-N-pyrrolidinyl-2-cyclohexenylidene)propenyl)-3 -ethylbenzoxazolium acid anion salt, 2-(3-(5,5-dimethyl-3-N-pyrrolidinyl-2-cyclohexenylidene)propenyl)-3 -ethylbenzothiazolium acid anion salt, 2-(3-(5,5-dimethyl-3-N-pyrrolidinyl-2-cyclohexenylidene)propenyl)-3H -indolium acid anion salt, 2-(3-(5, 5-dimethyl-3-N-pyrrolidinyl-2-cyclohexenylidene)propenyl)-1-ethylnaphtho(1,2-d) thiazolium acid anion salt, 4-(3-(5,5-dimethyl-3-N-pyrrolidinyl-2-cyclohexenylidene)propenyl)-1 -ethylquinolinium acid anion salt, 2-(3-(6-ethoxycarbonyl-3-(N-pyrrolidinyl)-2-cyclohexenylidene)propenyl)-1 -ethylnaphtho-(1,2-d)thiazolium acid anion salt and 4-(3-(5,5-dimethyl-3-N-pyrrolidinyl-2-cyclohexenylidene)propenyl)-1 -ethylquinolinium perchlorate.
 6. A polymethine dye selected from the dye compounds consisting of N-56 5,5-dimethyl-3-(3-(5,5-dimethyl-3-N-pyrrolidinyl-2 -cyclohexenylidene)propenyl)-2-cyclohexenylidene)pyrrolidinium acid anion salt, and N-(5,5-dimethyl-3-(5-(5,5-dimethyl-3-N-pyrrolidinyl-2-cyclohexenylidene)-1,3-pentadienyl)-2-cyclohexenylidene)-pyrrolidinium acid anion salt.
 7. The polymethine dye 1-(5,5-dimethyl-3-p-dimethylaminostyryl-2-cyclohexenylidene)pyrrolidinium acid anion salt. 